BBC hospital drama Casualty axed a storyline highlighting smoking risks, as actors were not allowed to light up indoors.

The show’s bosses were forced to pull the plug as it is filmed in Wales where – unlike in England – the ban on smoking in enclosed public spaces makes no exception for dramatic performances.

It emerged as the BBC, which moved production of the medical drama to Cardiff last year, called on the Welsh Assembly to amend the law.

Crews have to go to Bristol to film smoking scenes or use costly CGI techniques, as fake cigarettes are not realistic enough.

Clare Hudson, head of BBC Cymru Wales Productions, said: ‘What we are concerned about is that if we want the sky to be the limit for production in Wales, we need to be perceived as, and actually be, a can-do place where all things are possible in drama.

‘An independent company can go and make a show anywhere – with new tax breaks coming in there will be more American companies who make decisions utterly ruthlessly.

‘We may have a situation where our drama slate within Wales is potentially damaged by people making decisions on the basis of “oh, they won’t let us smoke, that’s a key part of this drama, let’s do it somewhere else”.’

Anti-smoking group Ash insisted that ban must remain in place however, in order to protect workers.

A spokesperson said: ‘This, we would argue, is a matter of convenience for the television industry – and health legislation should not be amended on commercial grounds.